The present invention relates to an arrangement to evaluate the received signal quality and more particularly to a data eye monitor for evaluating the signal quality of the received signal.
The term "data eye" is used in data signal evaluation to designate a pattern generated on an oscilloscope, which is triggered by the data clock and displays the received data waveform, when the data is not a simple repeating pattern. The resulting overlay of several traces on the oscilloscope produces a shape resembling a partially closed eye. The eye appears more closed when the data is distorted.
A data eye monitor is used in data transmission receivers and repeaters to monitor the size of the eye opening automatically providing a voltage proportional to eye opening which may be used for evaluation of the received signal. Uses include assistance in maual adjustment of receiver or repeater parameters, as part of an automatic receiver alignment system and as an evaluation of received signal quality.
No arrangement equivalent to the data eye monitor is known to exist. However, one of the functions of the data eye monitor is to predict error rate in a data receiver of a data transmission system. This is generally achieved by encoding the data for transmission in some way to include some known content which may be verified at the receiver, where errors in this content may be related to the number of data errors.